sparc64: Fix huge PMD to PTE translation for sun4u in TLB miss handler.

When we set the sun4u version of the PTE execute bit, it's:

	or	REG, _PAGE_EXEC_4U, REG

_PAGE_EXEC_4U is 0x1000, unfortunately the immedate field of the
'or' instruction is a signed 13-bit value.  So the above actually
assembles into:

	or	REG, -4096, REG

completely corrupting the final PTE value.

Set it with a:

	sethi	%hi(_PAGE_EXEC_4U), TMP
	or	REG, TMP, REG

sequence instead.

This fixes "git gc" crashes on sun4u machines.

Reported-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc/include/asm/tsb.h b/arch/sparc/include/asm/tsb.h
index b4c258d..e696432 100644 (file)
--- a/arch/sparc/include/asm/tsb.h
+++ b/arch/sparc/include/asm/tsb.h
@@ -157,17 +157,26 @@ extern struct tsb_phys_patch_entry __tsb_phys_patch, __tsb_phys_patch_end;
        andn            REG2, 0x7, REG2; \
        add             REG1, REG2, REG1;
 
-       /* This macro exists only to make the PMD translator below easier
-        * to read.  It hides the ELF section switch for the sun4v code
-        * patching.
+       /* These macros exists only to make the PMD translator below
+        * easier to read.  It hides the ELF section switch for the
+        * sun4v code patching.
         */
-#define OR_PTE_BIT(REG, NAME)                          \
+#define OR_PTE_BIT_1INSN(REG, NAME)                    \
 661:   or              REG, _PAGE_##NAME##_4U, REG;    \
        .section        .sun4v_1insn_patch, "ax";       \
        .word           661b;                           \
        or              REG, _PAGE_##NAME##_4V, REG;    \
        .previous;
 
+#define OR_PTE_BIT_2INSN(REG, TMP, NAME)               \
+661:   sethi           %hi(_PAGE_##NAME##_4U), TMP;    \
+       or              REG, TMP, REG;                  \
+       .section        .sun4v_2insn_patch, "ax";       \
+       .word           661b;                           \
+       mov             -1, TMP;                        \
+       or              REG, _PAGE_##NAME##_4V, REG;    \
+       .previous;
+
        /* Load into REG the PTE value for VALID, CACHE, and SZHUGE.  */
 #define BUILD_PTE_VALID_SZHUGE_CACHE(REG)                                 \
 661:   sethi           %uhi(_PAGE_VALID|_PAGE_SZHUGE_4U), REG;            \
@@ -214,12 +223,13 @@ extern struct tsb_phys_patch_entry __tsb_phys_patch, __tsb_phys_patch_end;
         andn           REG1, PMD_HUGE_PROTBITS, REG2;                        \
        sllx            REG2, PMD_PADDR_SHIFT, REG2;                          \
        /* REG2 now holds PFN << PAGE_SHIFT */                                \
-       andcc           REG1, PMD_HUGE_EXEC, %g0;                             \
-       bne,a,pt        %xcc, 1f;                                             \
-        OR_PTE_BIT(REG2, EXEC);                                              \
-1:     andcc           REG1, PMD_HUGE_WRITE, %g0;                            \
+       andcc           REG1, PMD_HUGE_WRITE, %g0;                            \
        bne,a,pt        %xcc, 1f;                                             \
-        OR_PTE_BIT(REG2, W);                                                 \
+        OR_PTE_BIT_1INSN(REG2, W);                                           \
+1:     andcc           REG1, PMD_HUGE_EXEC, %g0;                             \
+       be,pt           %xcc, 1f;                                             \
+        nop;                                                                 \
+       OR_PTE_BIT_2INSN(REG2, REG1, EXEC);                                   \
        /* REG1 can now be clobbered, build final PTE */                      \
 1:     BUILD_PTE_VALID_SZHUGE_CACHE(REG1);                                   \
        ba,pt           %xcc, PTE_LABEL;                                      \